This invention relates to devices for the dispensing of liquids into a carrier fluid. While the invention is applicable to the release of all kinds of active materials into a liquid or gaseous carrier fluid, it is particularly concerned with the dispersal of liquids for scenting the fluid or for freshening the surrounding atmosphere.
It is known to deliver materials, in particular liquids, into the surrounding atmosphere in a variety of ways, for such purposes as freshening or perfuming the air. For example, aerosol sprays are used, but they have a tendency to produce large droplets of the liquid which, because of their weight, do not travel far from the spray zone. Furthermore, the carrier gases used in aerosols may be environmentally harmful.
Fragranced gels are also used as a static source for the delivery of volatile substances into the atmosphere. They operate continuously, which is not always required, however, and their effectiveness decreases with time. They also have the disadvantage that it is not usually possible to vary the intensity of delivery.
Electrically heated devices and candles are other known means which use heat to release fragrances into the atmosphere. The materials to be dispersed must be stable at the elevated temperatures experienced and this sets severe constraints, in particular on the type of fragrances which can be used.
In one aspect of the present invention, a dispensing device is provided to disperse a liquid into a carrier fluid flow, the device comprising a container for the liquid, a carrier fluid entry conduit opening into the container for directing a pressure flow into the container, an outlet from the container for said fluid, a conduit for the liquid within the container having an outlet in the influence of the flow through said carrier fluid conduit whereby said flow takes up liquid from the liquid conduit to disperse it in the carrier fluid flow.
The device may be provided with its own carrier fluid pumping means so as to operate as a self-contained unit. It is also possible, however, for the device to form an auxiliary unit which can cooperate with other apparatus producing the carrier fluid flow. For example, a device according to the invention can be arranged to be actuated by the air flow from the vacuum cleaner, or a ventilating fan, or by steam as from a humidifier, or from a water flow as in the piped water supply to a bath or a shower or a water closet.
The conduit may take the form of one or more capillary passages, so that liquid can be drawn by capillary action towards the conduit outlet to be available substantially instantaneously on start-up. The capillary action can also reduce any loss of the liquid from the container during periods when the carrier fluid does not flow through it.
In one form of the device, intended to dispense a liquid into a gaseous carrier fluid such as a flow of air, the carrier fluid entry conduit terminates in an upper region of the container, above the level of the liquid to be dispensed, and the liquid conduit extends from a bottom region of the container, to said entry conduit termination above the liquid level.
The device may comprise means for capturing larger droplets entrained in the gaseous flow so that the flow leaving the device contains the liquid in the form of a fine aerosol or a vapour, in which the average size of the particles may be not be substantially greater than, for example, 10 microns, to delay precipitation from the air flow. Because the dispersal of the liquid is effected by the forced gaseous flow from the device, it is possible to control the rate of dispersal, so permitting large spaces to be treated rapidly and allowing the dispensing of the liquid to be stopped rapidly if so required.
It is sometimes desirable to be able to vary the material being dispensed. Although this can be done easily with passive dispensing devices, such as containers from which the material, eg. in a fragranced gel, is dispensed simply by exposure to the atmosphere when the container is opened, it is more troublesome to make the change with an active dispensing device such as the electrically heated device referred to earlier, where the material in the device must be replaced.
According to another aspect of the invention, a liquid dispensing device is provided comprising a carrier fluid inlet for communication with a plurality of carrier fluid entry conduits arranged in parallel and opening into respective containers for liquids to be dispensed into the carrier fluid, within each container a conduit for the liquid having an outlet in the influence of a carrier fluid flow through the associated entry conduit for dispersing the liquid into said flow, and an outlet for said flow carrying the liquid dispensed, means being provided for directing the carrier fluid through said entry conduits selectively.
Thus, in contrast to known air freshening devices which are able to provide only a single fragrance, or which require cumbersome and time-consuming manipulation to change the fragrance to be dispensed, it is possible to choose an alternative fragrance in a simple and almost instantaneous manner.
The means for selection may be arranged to allow the carrier fluid flow to be directed to two or more containers at a time, so that the user is able to dispense combinations of the fragrances available if desired.
In a further aspect of the invention, a liquid dispensing device is provided comprising means for generating a carrier fluid flow, a replaceable capsule removably connected to a fluid flow exit from said generating means, said capsule forming a container for the liquid to be dispensed and comprising means for dispensing the liquid into the flow from said exit, the capsule having an outlet for directing the flow carrying the liquid to the exterior.
Employing a removable capsule as the liquid container it is possible to provide a device which can be set up and operated in a particularly simple manner. Preferably, the capsule has fluid-tight seals on said outlet for the combined flows and on an inlet, and means are provided in the device for breaking said seals upon insertion of the capsule into the device.
The capsule can be formed with respective passages for the liquid to be dispensed and for the flow from the generating means, the liquid passage having an outlet end disposed in the region of said carrier fluid flow into which the liquid is drawn by venturi or jet pump action. Conveniently, the liquid passage is formed by one or more capillary conduits.
In an arrangement of a device according to the invention having means for dispensing liquid from alternative containers, the containers can be provided in the form of disposable sealed capsules, so that replacement of a capsule provides a ready means of changing the liquid to be dispensed. The use of the device can be further simplified if a set of capsules for the respective fluid entry conduits is provided as a single unit.
It will be understood that if devices according to the invention are arranged to be operated with disposable capsules of the liquid to be dispensed, they may be supplied, at least initially, without capsules which would be obtainable separately by the user.
According to yet another aspect of the invention, a liquid-containing capsule is provided for a liquid dispensing device, the capsule comprising an inlet conduit for admitting a flow of carrier fluid into the capsule interior, a conduit for the liquid to be dispensed, preferably comprising at least one capillary passage, having an exit opening exposed to said carrier fluid flow within the capsule for the dispersal of the liquid into said flow, and an outlet opening for the carrier fluid flow carrying the dispersed liquid.
When operating with a forced gaseous flow as the carrier fluid, it can be conveniently arranged that the liquid conduit projects upwardly above the level of the liquid in the capsule to adjacent an opening through which the carrier fluid enters the interior space of the capsule in an upper region, above the top of the liquid in the capsule. The liquid to be dispensed may be arranged to be drawn into the carrier fluid flow generating a reduced ambient pressure in the region of the exit from the liquid conduit, as by venturi or jet pump action.
In one preferred form, the capsule also has a barrier member located in a direct path between said conduit exit and the outlet opening, so as to deflect the carrier fluid flowing towards the exit. Larger droplets of liquid entrained in the flow will impinge on the barrier member and fall back into the main body of liquid the remaining, more intensely dispersed liquid in the flow from the capsule being carried further from the capsule as the flow dissipates into the surrounding atmosphere.
In a preferred construction, the capsule has a body formed by a pair of wall members sandwiched together to define an interior space within which the liquid is held. It is also preferred to form the liquid conduit on an internal member which is inserted into the body of the capsule. The internal member may comprise means locatable on said inlet conduit in order to ensure the liquid conduit outlet is held in close proximity to the outlet from the carrier fluid conduit.